Check your SanDisk cards if using a Canon EOS R5 Mark II. This warning is from Canon USA:
Corrupted images captured with EOS R5 Mark II and certain SanDisk SD cards
Thank you for choosing Canon products.
Still images taken with Canon EOS R5 Mk II may be recorded as corrupted/abnormal due to incompatibility of certain SanDisk Extreme PRO SDXC UHS-II 64GB, 128GB and 256GB V60 cards.
For more information, please see the link to SanDisk support:
To learn about compatible SanDisk Memory Cards for EOS R5 Mark II, please visit the below link.
Learn About Compatible SanDisk Memory Cards for the Canon EOS R5 Mark II Camera | SanDisk
This information is only for residents of the United States and its five territories. If you do not reside within these areas, please contact the Canon Customer Support Center in your region.
Thank You,
Service Strategy & Support Group
Canon U.S.A., Inc
The SanDisk page shares the following:
Steps to Resolve SanDisk Extreme PRO® SDXC™ UHS-II V60 64, 128, and 256GB Still Image Problem with a Canon EOS R5 Mark II
View the Use of Third-Party Software or Websites disclaimer.
SanDisk Support cannot help with third-party software or hardware.
Description
Still images taken with a Canon EOS R5 Mark II may be recorded as abnormal images due to the incompatibility of certain SanDisk Extreme PRO® SDXC™ UHS-II 64GB, 128GB and 256GB V60 cards.
Affected Cards
SanDisk Extreme PRO® SDXC™ UHS-II V60 64GB
SanDisk Extreme PRO® SDXC™ UHS-II V60 128GB
SanDisk Extreme PRO® SDXC™ UHS-II V60 256GB
Need more help?
Answer ID 52427: Learn About Compatible SanDisk Memory Cards for the Canon EOS R5 Mark II Camera
Resolution
Warranty Replacement
Contact Us for Warranty Replacement.
(Thanks, Perry!)